Student Research

Characterization of Outer Membrane Vesicles In Probiotic Esh

Outer membrane vesicles are spherical structures that are constitutively produced by all Gram negative bacteria. They range from 10-300 nm in diameter and have been shown to be an alternative transport system for secreting proteins into the extracellular space. Outer membrane vesicles are monoluminal and are composed of proteins, DNA, phospholipids and lipopolysaccharides. Although their exact function remains unclear, it has been proposed that they play a role in pathogenicity as well as cell signaling between bacteria. The probiotic bacterium, E. coli Nissle 1917 (EcN), has been observed to produce outer membrane vesicles. EcN is currently being marketed under the brand Mutaflor® in order to alleviate gastrointestinal ailments such as ulcerative colitis and irritable bowel syndrome. Recently, the full genome of EcN has been sequenced and has been found to have high homology with Uropathogenic E. coli strain CFT073 (UPEC). UPEC is the leading cause of urinary tract infections in humans and has the potential to cause renal failure when left untreated. UPEC is slowly building antibiotic resistance which is why researchers are exploring the option of vaccine development. Both microbes have been observed to produce autotransporter proteins as well as outer membrane vesicles. This study aims to characterize outer membrane vesicles of EcN in comparison to the outer membrane vesicles of its closest genetic relative, uropathogenic E.coli strain CFT073 by studying their physical properties, their protein composition, and their roles in biofilm formation.


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